1. Relationship between patient volume and quality of treatment (in Norwegian),1993
2. Variation in outcome of surgical procedures;Houghton;Br J Surg,1994
3. Are Large Hospitals Better than Small?;Järhult,1995
4. Effect of surgical experience on the results of resection for oesophageal carcinoma;Matthews;Br J Surg,1986
5. Argumentation für eine regionale zentralisierte Behandlung beim Magenkarzinom. Eine statistiche Untersuchung von nationalen Resultaten;Slisow;Zenlralbl Chir,1987